The politically toxic issue of where new airport hub capacity should be located in the UK, being too difficult a decision for politicians to make, has been given to an Airports Commission set up by the UK Government and led by Sir Howard Davies.

The Western Gateway Group submitted a proposal to the commission based on an expanded Cardiff Airport linked to London by a high speed rail line (HS3).

Before the end of the year the Davies Commission will publish a short list of options for future runway capacity, but we now have strong indications as to what those options might be.

Sir Howard doesn’t think that regional airports – proposals were also submitted by Birmingham Airport – can provide the extra capacity that the UK needs.

He believes that new runways will need to be built in the south east of England, which suggests new runways at either Heathrow, Gatwick or Stansted.

Sir Howard is still undecided about a new airport in the Thames Estuary, the so called Boris Island.

So far, so conventional, because these are the same options that have been looked at for the last 40 years and have been impossible to build because they are either too expensive, environmentally damaging or the airlines just don’t want to go there.

This triumph of hope over experience may well continue a policy of do nothing, because whilst Sir Howard has given the issue a thorough examination, the chosen option may well be undeliverable.

It may have been better to retain the regional options because planned expansion may be better than forced expansion when extra capacity in the south east can’t be delivered.

If the Davies Commission fails to grasp the nettle of Heathrow – and in that it has a choice between the impossible (expansion) and the unlikely (closure) – then traffic will spill out to not only the other airports in the south east of England but also to regional airports.

So what does the future hold for Cardiff Airport, with airport capacity concentrated in the south east of England?

It doesn’t mean an end to the expansion of Cardiff Airport. There is still a need for a regional airport in the west of the UK that can address all markets including long haul.

Should Sir Howard want to move passengers away from Heathrow to other south east airports or even proposes a new airport site in the Thames Estuary, then a successful Cardiff Airport providing connectivity for Wales and the west of England becomes even more important.

Cardiff will need to fight for every passenger it can get. The weapons it will need will be improved surface access and the devolution of air passenger duty.

We have already seen how improved surface access makes the airport more attractive for passengers with the introduction of the Airport Express bus service. Cardiff Airport now has a turn up and go bus service that is as good as any inbound passenger would expect.

The Western Gateway proposal set out a number of ways that surface access can be further improved as passenger numbers increase, including a spur from the Vale of Glamorgan rail line, a spur from the Great Western main line and improved road access from Junction 34 on the M4.

The issue of air passenger duty (APD) is more crucial. The Silk Commission, the UK Government commission looking at increased powers for Wales, has recommended to the UK Government that APD is devolved to the Welsh Government for long haul flights.

The Welsh Government could then set any rate that they wish including zero. The issue of short haul APD is to be considered by the Davies Commission.

The UK Government hasn’t yet given a response to the Silk Commission proposals but should be considering the effect of concentrating airport development in the south east of England and high speed rail investment on a north-south axis in the UK.

Any investment in airports or high speed rail in England without a corresponding investment in Wales will put Wales at a competitive disadvantage compared with other parts of the UK.

To not give Wales control of important tax varying powers to counter the improved connectivity being provided for England would signal that the UK Government does not consider it important to have prosperity throughout the whole of the UK.

Martin Evans is Visiting Fellow at the University of South Wales and a member of the Western Gateway Group.